Micrometer spindle locking device

ABSTRACT

The spindle of a micrometer caliper is locked in place relative to the micrometer frame by a simple, linear motion operated locking slide. The slide has a cam surface which directly engages the spindle, thus restraining it from both linear and rotative motion.

I a l l. W l u w it ties tel [151 3,63 Forum 51 Jan. H8, 1972 [5 MICROETER SPINIDLE LUCKHNG References Cited DEVICE UNITED STATES PATENTS Inventor: Amhflny Paml'e, Ha'tfmd, 2,856,694 10/1958 Bianco ..33/l64 R [73] Assignee: Pratt & Whitney llnc., Hartford, C 4 7,105 6/1892 Darling ..33/143 J [22] Filed: D 2, 1969 Primary Examiner-William D. Martin, Jr. 1 pp No'z 881 478 Attorney-Harry R. Dumont [57] ABSTRACT 2 US. Cl. ..33 164 R {2 Int Cl Gm/b 5/00 The spindle ofa micrometer caliper is locked in place relative Fieid 1 167 169 143 J to the micrometer frame by a simple, linear motion operated 5 locking slide. The slide has a cam surface which directly engages the spindle, thus restraining it from both linear and rotative motion.

llll HT "TENTH-M18872 3,634,943

F'IGJ Ina" 5y MRDWT MICROMETER SPINDLE LOCKING DEVICE BACKGROUND OF THE INVENTION This invention relates to an arrangement for locking the parts of a micrometer in their adjusted position for preserving in place a measurement taken. Prior art arrangements of this type involve either setscrew-type securing devices or devices which involve a rotative manipulative type of adjustment to lock and to unlock the micrometer. Examples of the former are shown in US. Pat. Nos. 2,541,82l and 2,943,395. Examples of the latter are disclosed in US. Pat. Nos. 7l7,296 and l,402,665.

SUMMARY OF THE INVENTION My invention provides a micrometer locking device and arrangement of simplified and reliable construction in the form of a cam locking slide. The slide is directly engageable with the periphery of the spindle and secures the spindle against both rotative and longitudinal movement relative to the frame. The movement required of the operator is a simple linear movement which may be effected without disturbing the accuracy of the reading preset on the micrometer.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side view of a micrometer of standard construction, incorporating a locking device constructed in accordance with my invention;

FIG. 2 is a partial sectional view taken along the line 2-2 of FIG. I; and

FIG. 3 is a perspective view of the locking slide used.

DESCRIPTION OF THE PREFERRED EMBODIMENT AND ITS OPERATION In FIG. I, the micrometer shown includes the frame which is of a U-type shape, the anvil 12, the spindle l4, and the sleeve 15. A bearing portion 16 incorporated in frame 10 journals spindle 14 within a longitudinal bore. A barrel 18 is further fixed to frame 10 through bearing portion 16. Spindle I4 is in screw-thread engagement with the end of barrel l8. Sleeve 15 is connected with spindle 14 to tumwith it as the micrometer adjustment, in accordance with normal practice, is made. Both the side of barrel I18 and the left-hand hand beveled end of sleeve 15 are graduated in the usual manner as shown to provide decimal readout. Cylindrical locking slide 20 is shown in the position in which it is mounted in the bearing portion 16 of the micrometer with its axis transverse to the axis of spindle 14.

FIGS. 2 and 3 show the detail of locking slide 20 and its operative engagement with spindle l4 and bearing portion 16 of frame 10. Slide 20 is seated in a cylindrical bore 21 extending laterally through bearing portion 16. Slide 20 is shown in its right-hand, locked position. A recess on the periphery of the spindle which is partially defined by a flat surface or upper cam portion 22 which is inclined toward the axis of the locking slide. The locking action is provided by the engagement of upper cam portion 22 of slide 20 with the lower periphery of spindle 14. Cam portion 22 is preferably milled in slide 20. The locking pressure exerted by slide 20 is directly applied to spindle l4, securely locking it against both rotation and translation relative to frame 10. In its left-hand, unlocked position, it will be seen that slide 20 has its upper cam portion 22 maintained away from engagement with the lower surface of spindle 14 so that the spindle is free to rotate and to move longitudinally. The recess is further defined by lip portions 24a and 24b form stop limits to the respective leftward and rightward movements of slide 20 to retain ti within bore 21. It is significant to note that the position of locking slide 20, whether engaged or not, is such that it does not interfere with the movements made with the micrometer to align it with the objects to be measured. The simple tapping motion required at the end of slide 20 does not disturb or affect the accuracy of the measurement being taken such a would occur in prior art devices when a complex and rotative operator motion IS required to engage and apply torque to the locking device to render it operative.

A further important advancement and improvement is afforded by the construction of my locking device in that it provides an increased bearing surface, i.e., line contact through the engagement of the flat surface or cam portion 22 with that of spindle 14. The holding power is thus greatly increased over that applied by prior art single-point contact devices. Furthermore, to lock the spindle, a user need only axially push on one end of the slide, and to unlock the spindle, a user may axially push the other end of the slide, or because of the geometry of the arrangement, simply rotate the spindle (counterclockwise rotation as viewed in FIG. 2). This latter method of release greatly facilitates operation of the micrometer.

It will thus be seen that I have provided by my invention a novel and improved locking arrangement for a micrometer.

Iclaim:

1. In a micrometer, the combination of:

a frame having a longitudinal bore and laterally extending bore partially intersecting the longitudinal bore;

a spindle mounted within the longitudinal bore for rotation and axial movement therein such that a portion of the spindle is received by the laterally extending bore;

a cylindrical locking slide mounted within the laterally extending bore, with the ends of the slide protruding therefrom, for axial movement therein relative to the spindle between locked and unlocked positions, the locking slide having a recess on the periphery thereof defined by a flat surface inclined toward the axis of the locking slide such that a line of contact is established between the flat surface of the locking slide and the periphery of the spindle in a locked position of the slide, the surface is spaced from the periphery of the spindle in an unlocked position of the slide, and the locking slide is axially displaced from a locked position to an unlocked position by rotation of the spindle in a predetermined direction; and

whereby the spindle may be locked by pushing on one end of the slide and unlocked by either pushing on the other end of the slide or rotating the spindle. 

1. In a micrometer, the combination of: a frame having a longitudinal bore and laterally extending bore partially intersecting the longitudinal bore; a spindle mounted within the longitudinal bore for rotation and axial movement therein such that a portion of the spindle is received by the laterally extending bore; a cylindrical locking slide mounted within the laterally extending bore, with the ends of the slide protruding therefrom, for axial movement therein relative to the spindle between locked and unlocked positions, the locking slide having a recess on the periphery thereof defined by a flat surface inclined toward the axis of the locking slide such that a line of contact is established between the flat surface of the locking slide and the periphery of the spindle in a locked position of the slide, the surface is spaced from the periphery of the spindle in an unlocked position of the slide, and the locking slide is axially displaced from a locked position to an unlocked position by rotation of the spindle in a predetermined direction; and whereby the spindle may be locked by pushing on one end of the slide and unlocked by either pushing on the other end of the slide or rotating the spindle. 